[Nasrudith]

Unfortunately there are all sorts of other material properties to worry about beyond raw durability/'quality'. Natural rubber tires react quite poorly to hydrocarbons and greases, let alone traction issues. And that is putting aside the logistical issues with getting sufficient natural rubber.

There may be some sort of "compromise" material that could be developed that would lack the toxicity or microplastics issues without compromising safety, but I'm going to defer to experts in that field.